Telephone system.



A. H. DYSON.

.TELEPHONE SYSTEM. 7 APPLICATION FILED D20. 4, 1906.

Patented Nov. 8, 1910,.

4 SHEETS-SHEET 2Q A. H. D YSON'. TELEPHONE SYSTEM, APPLICATION FILED DEG. 4, 1906.

Patented Nov. 8, 1910.

4 SKEBTS-SHEET 3.

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TELEPHONE SYSTEM.

7 APPLIOAILON E1LE1).1 E0.4, 1906. 975,338, Patented Nov. 8, 1910;

4 SHEETS-.BHEET 4.

. UNITED STATES PATENT OFFICE.

ALFRED H. DYSON, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASQIGNMENTS, TO KELLOGG SWITCHBOARI) & SUPPLY COMPANY, A CORPORATION OF ILLINOIS.

'rnnnrnonn sYsrnM.

To all whom it. may comm:

Be it known that I, ALFRED H 'DYsoN, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented new and useful Improvementsin Telephone Systems, of which the following is a specification.

' The present invention relates generally to telephone exchange systems of the so-called calling subscriber and any other desired line,

and has to do more particularly with that class of automatic systems in which the sub scribers lines are divided into groups and a relatively small number of connecting switches is assigned to each group under they control of a master-switch which, up'o'nthe initiation of a call, will'start an idle connecting switchto pick out and establish connection with the calling line. of thischaracter heretofore proposed, either the master-switch has been incapable of starting a second selecting switch after a second ca ling lin-e until the first connecting switch has completed its operation, or, so constructedthat when it returns to its normal'position after setting a connecting switch in operation, it will, in case said connecting, switch had not completed its operation, immediately set a second connecting switch in operation to establish connection with the same calling line. In the former case, much time is lost in making connections, while in the latter case the switches are unnecessarily operated.

I One object of the present invention is to provide a novel master-switch mechanism which shall be free from these defects.

The master-switch mechanism herein disclosed will, upon reaching its normal position after-having set a connecting switch in operation, immediately set asecond switch in operation to establishconnection with a second calling line, incase a' second call has come in, without waiting. for a previously started connecting switch lto complete its 7 connection with the first calling-line.

My invention also com-prises certain novel.

circuit arrangements and .minor details which will, together with the above, be more Specification of Letters Patent.

selecting switch.

In systems fully understood fupon reference to the following descriptionv taken in connection with the accompanying drawing. 1 Y

Referring to said drawing, Fi ure 1, which includes parts 1 and 2, is'a iagram of a so-called semi-automatic systemiembodying the features of my invention; Figs.

2, 3 and 4 are elevationsof the connecting, or line selecting, switch diagrammatically illustrated in Fig. "1, each view being taken froma different side; Figs. 5 and 6 are front and side elevations respectively ofthe referred niaster-switch for controlling the ine Patented News, 1910. Application filed December 4, 1906. Serial K0 346365 selecting switches; Fig. .7 is a partial sec-.

tional v ew of a line'selecting switch illustrating in plan the primary magnet together with its associated mechanism, the section. being taken on a plane indicated by the line 7-7 of Fig. 3; and F ig. 8 is a detail of the oil-normal switch associated with said line Throughout these views, like characters refertolike parts. f

vReferring to the drawing and more particularly to the diagram of Fig. 1, 'A'designates the substation'equipment of two telehone lines which terminate at the exchange in multiple jac'ks and in multiple contacts of line selecting switches. Connection is obtained betweena calling and a called line through the agency of the master-switch mechanism B, the line selectin switches C and the manually operated lin -circuit apparatus D. In practice, the subscribers lines are divided into groups'of, say, one hun dred, and each group of one hundredj'lines is provided with ten line selecting switches C under the control of one master, or con- "trol, switch B. With this arrangement,each

subscribers line would be multlpled to ten -line selecting switches. ,It is-of course to be understood that these values may be varied to suit any required condition. Briefly stated, the operation of establishing connection-between the calling and the called line involves the following steps: The calling party removes his receiverand thereby,

switch B,sets an idle line selecting switch G into operation to automatically pick. out and establish connection with the calling line, 1

thereby extending thec'alling linecircuit to througl the agency of the control or masterthe wipers A are 10-11 coeperating making the usual busy test of the desired calledline, completes the connection or notifies the calling party of the busy condition of the liner During conversation, supervision is had in the usual way; and at its termination, all the parts are restored to normal.v

In the particular embodiment of the invention herein presented, the control switchmechanism B comprises a pair of wipers with two sets of bank contacts 12-13, together with a motor magnet-M for moving the wipers over their associated bank contacts,-a control relay R by which thecircuits of the motor magnet are controlled, a release magnet RM by which returned to normal, and a differential control relay GB for governing the action of the relay R.

The line selecting switch C comprises the fixed, or bank, contacts 14, 15, 16 and 17 with which the wipers 18, 19,20 'and21 respectively cooperate. in making connection between the link-circuit strands L -.-L and the limbs T'T of the calling line, The wipers 19,20 and 21 are given both a primary movement and a secondary. movement in response to the energizations and demagnet PM respectively.

and the secondary magnet SM By the primary movement, these wipers are v. the group I so - contact 14; then wiper 18 movement. tacts 14, 15, 16 and 17 corresponding bank contacts of othen line' stepped to that group of'bankcontacts in which the calling line contacts are located; and .by the secondary movement, they are moved over the contacts of theselected group until the calling line contacts are encountered. I The selection of the group is obtained through the provision of the passive contacts 14, each'of which corresponds to a group of bank contacts; and the wiper 18 co operates with these in .selecting the group in which the calling line contacts are located. Normally,-

the contacts 14 and 15 are grounded but as soon as a call is initiated, thecontact 15, corresponding to the calling line, and the contact 14, corresponding to in which the contacts 15 calling lmeare located, have their normal grounds removed. Thus, in the operation of the switch, all the wipers are stepped around until the wiper 18 engages an ungrounded the wipers 19,20 and'21 takes place and is continueduntil the wiper 19 engages the mi grounded contact 15 of the cal ng line, the not partaking ofthis: secondary As illustrated, the bank conaremultipled to the selecting switches in the cup. One such set of bank contacts is in icated at 14', 15, 16' and 17'.

The-link-circuit equipment D may consist of any preferred apparatus and arrangement of I the battery B.

maybe traced from the live net and closed contact 32 to ground.

of the.

circuits and in the present instance consists in general of a four relay circuit of well known construction.

Considering the operation of the system i more in detail, it will be observed that the removal of the receiver 22 from its switchhook 23 at the substation of the calling party (which may be assumed to be that at the left of the diagram) completes a bridge mal contact 30of relay 29 and winding of relay 31 to ground and the return side of The closing of this circuit energizes the relay 31 sufiiciently to cause the attraction of its contacts 32, 33, 34. The movement of contact 34 to its closed. position completes a locking circuit for the relay 31 which extends from the live .pole of the battery B through resistance 27, contact 35, closed contact 34 and winding of relay 31 to ground, thereby preventing interfer-' ence with the energization of said 'relay from the substation. Contact 32, upon being movedto its closed position, completes a circuit for the control magnet 36, which pole of the batthrough the winding' of said mag- Magnet 36'is thereby energized to attract' its grounded contact 37 to remove the normal ground from the corresponding to .t, e calling line. Contacts 15 15, corresponding to this line, are normally grounded over a path extending through normal contact 33; The movement tery B,

roup contacts 14-14 I of the contact 33 toits alternate position upon the energizationof relay 31. therefore removes the normal ground from these contacts 15-15 and also provides a' path for current by which the control rela OR of the master-switch mechanism B W1ll be energized. This circuit extends from the live pole of the=battery 'B, the secondary movement of through the winding 38 of said relay,'resistance 39 and alternate contact 33 to ground. As illustrated, nor-.

'mally there is-no closed circuit including the windin 40 of the control relay CR. Gonsequentiy, the completion of the circuit through the winding 38 energizes the said relay sufiiciently'to moveits contact'41 to its closed position, thereby completing a circuit through'the winding of the relay R --which may be trac'd from the live pole of the battery 13 through the winding of said relay, closed jcontact 42 and contact 41 to ground. Relay R is thereby energized and its contacts 43 and 44'moved to theimalterat contact 50 and the wipers 10 and 11. will 54 and 55.

'43 to its alternate position closes a Vibratory circuit through the motor magnet M which maybe traced from the live pole of the battery B through the winding of said magnet, the vibratory contacts and alternate contact 43' to ground. By reason of the mechanical relation of the parts hereinafter more particularly pointed out, the closing of the circuit through the motor magnet M causes the wipers 10-11-to he stepped OVEI their associated bank contacts 12 and 13 respectively. Upon the energization of motor magnet M, contacts 46 and 47 are closed and immediately thereafter contact 42 is opened, so that the circuit "for relay R now extends from the winding of said relay through alternate contact 44. losed contact 46, wiper 10 to the engaged contact 12' associated therewith.

The contacts 12 and 13 are connected by conductors 48 and 49 with the circuits of the hne selecting switches C. If the line selecting switch, corresponding to the contactli" first encountered, be busy, its switch contacts50 and 51'will be in their abnormal positions and the engaged contact 12 will be grounded by way of the closed contact 50.

Thus, so long as the wiper 10 engages the contacts 12 associated with busy line selectmg switches, a circuit will be maintained through relay R and hence through motor magnet M, and the movement of wipers 10-1-1 continued. As soon, however, as a contact 12, associated with an idle line selecting switch is encountered, the maintaining circuitfor relay R will be interrupted stop inengagement with contacts 12 and 13 respectively, corresponding to such line selecting switch. As soon as an idle line selecting, switch C is thus selected, a circuit Wlll be completed through the winding of its primary relay PR, which circuit may be traced from the live pole of the battery B through the winding of said relay, closed contact 51, engaged contact 13, wiper 11, closed contact 47, normal contact 43 to ground. The energization of the relay PR" causes the attraction ofits contacts 52, 53,

plete's a path for current through the wind The closing of contact 52 coming 40 of the diiferentialcontrol relay CR,

through the resistance 56, closed contact 52 to ground. As soon as this takes place, the currentfiows through the windings 38 and 40 of the control relay are substantially equal in their magnetizing effects; and the.

armature contact 41 of said relay is allowed to return to its normal position. The equalization of the magnetizing effects is brought about by suitably proportioning the resistances39 and 56, and other partsjincluded in the parallel grounded branches. The openmg of contact opens a possible circuit for the secondary relay SR, while the closing of the contact 54 completes a vibratory circuit for the primary magnet PH which may be traced from the live pole of the battery B, through the winding of said magnet, the vibratory contacts 57 and closed contact 54 to ground. The repeated energizations and deenergizations of the primary magnet PM, resulting from the closing of this circuit. cause the wipers 18, 19, 20 and 210t' the line selecting switch to more ste i-by-step in a primary direction. Upon tie first movement of the wipers, the contacts 50 and 51 of the primary cit-normal switch P0 are moved to their abnormal position, and the energizing circuit of the primary relay PR is interrupted at contact 51: but a maintaining circuit for this relay is continued from the relay winding through the closed contact 53 to wiper 18 If the first contact 14. engaged by the wiper'18, be the contact of the group in which the contacts 15, 16 and 17 of the call- ;ing line are located, the maintaining circuit [will be interrupted atthe open contact 37 of the relay 36 associated with the calling line. Under such circumstances. the relay PR" will be deenergized. and the further movement of the wipers in a primary direction discontinued. On the other hand, if the'first group contact 14 is not that associated with the calling line, the circuit of the prinzary relay PR will be extended from the wiper 18 through contact 14 and the as sociated contact 37 of relay 36 to ground. Thus a circuit will be maintained forthe primary relay PR so long as the wiper 18 passes over grounded contacts 14, As soon, however, as an ungrounded contact is en countered, the .movement of the switch wipers in a primary direction will be discontinued, as before indicated. In this connection, it should be noted that the engag ing portion of the wipers 18 is'ot sufficient width to engage .a second contact 14-before leaving the first, so that the maintaining circuit of the primary relay is only interrupted at the relay contacts 37. As soon as the line selecting switch has made its first primary movement, a circuit is completed for the re lease magnet RM of the master-switch mechanism B which may be traced from the live pole of the battery B, through the winding of said magnet, normal contact 44, closed contact 46, wiper 10, contact 12 and closed contact 50 to ground. The release magnet RM is thereby energized and, due to the mechanical relation of the parts, the contacts 4647 are restored to their normal posi tlons; and upon 1ts.de 'nerg1zat-1on, due to I the breaking of its circuit at contact 46, con tact 42 is again closed, and the wipers 1011 areallowed to return to. their normal position under the influence of a retracting spring. Thus it will appear that as soon as the selected line selecting switch has, made its first movement, the master-switch is restored to 'its normal position and is available for the handling of other incoming calls. For example, if a second call is in itiated over a line having access to the master-switch mechanism 'B, a branch path to ground for the winding 38 of the control relay CR would be completed through the completed and the wipers 10-11 again set in operation to select a second idle selecting switch to set it in operation to care for the second call. It will also be apparent from the description that in case no second call has been initiated by the time the masterswitch is restored to normal, it will not be again set in operation to start a second line selecting switch.

Referring again to the operation of the line selecting switch C, it should-be noted that the first primary movement of the switch wipers will be instrumental in moving the contacts 596O of the release switch 1 RS" to their abnormal positions. Therefore, upon the deenergization of primary relay PR, the grounded branch through the winding 40 of the control relay CR will not be discontinued by reason of the opening-of contact 52, but will extend through normal contact 61 ot the secondary off-normal switch S0 and alternate contact 59 of the release switch RS to ground. By this means,the balanced condition is maintained in the control relay CR. Upon the denergi-- zation of the primary relay PR, the maintaining circuit of said relay willbe interrupted .by the opening of contact 53; the vibratory circuit of the primary magnet PM will be interrupted by the opening of contact 54; and by the closing of contact 55, a circuit will be established for the secondary relay SR. This circuit may be traced from the live pole of the battery B, through the winding of said relay, closed contacts 58, 55 and 50 to ground. The closing of this circuit will cause-the relay SR to move its contacts-'62, 63, 64, 65 and 66 to their at tracted positions. The movement of contacts .65'and'66 interrupts the strands LL the associated link-circuit and thereby disconnects the wipers 20 and 21 so as to prevent possible interference with conversar tions existing over the multiples of the contacts over which said wipers pass. The clos- King of contact 62 provides a path in bridge of cont-act 61 which is opened upon the first secondary movement of the switch wipers. The closing of contact 63' completes a circuit for the secondary magnet SM which extends from the live pole of battery- B through the winding .of said magnet, its

- vibratory contact 67, closing contacts 63 and 59 to ground. The energization of, this magnet, by reason of the vibratory character of its circuit, advances the wi ers 19, 20 and 21 one step in a secondary 'irection, thereby bringing wiper 19 into engagement with the first contact 15 corresponding to the row in which the calling line contacts are located. Since the first primary movement of these wipers causes the contacts of the secondary ofl'-normal switch S0 to be moved to their abnormal positions, the initial energizing circuit of the secondary relay SRis interrupted at contact 58. However, if the first contact ,15 engaged by wi er 19' is. grounded, amaintaining circuit or the relay SR will exist. This circuit extends from the live pole 'of the battery B through the winding of said relay, alternate contact 6 1, wiper 19, engaged contact 15 and normal contact 33 of relay 31, to ground. Since the ground is removed only from the .contact 15 corresponding to the calling line, the secondary movement of the wipers will continue until the wiper 19 enga es econhen this occurs, the maintaining circuit just traced will be interrupted at contact 33 of the relay 31 of the calling line. Thereupon the circuit for thesecondar'y magnet SM will be interrupted-at contact 63 and the further movement of the switch wipers in a secondary direction discontinued. As soon as contact 66 closes, a path for current will exist from the battery B associated with the link-circuit apparatus D, through protective resistance 68, normal contact 69 oi'supervisory relay 70, 'contacts 71--72 of supervisory relay 73, link-circuit strand L wiper 21, contact 17 and the winding of cut-ofi' relay 29 to ground. Relay 29 will thereby be energized to attract its contacts 28, 30 and 35. By the opening of the latter, relay 31 will be deenergized and the parallel path through the winding 38 of relay CR and resistance 39 will be interrupted by the opening of contact 33. At substantially the same time, the parallel path through the other winding 40 of relay CR and resistance 56 will be interrupted at contact 62. If de sired, the relay CR may be made slow-acting so as to give sufiicient time for the operation of relays 29 and 31 to enable the parallel branches. to be simultaneously inter-I rupted.- As soon" as this interruption takes place, the relay GR is left in a denergized condition, in so far as the circuits of-this particular connection are concerned.

The energization' of cut-off relay 29 interrup'ts the normal control circuit through the substation and extends the circuit of the -relay 29 of the calling line is energized, an

additional path for current will extend from the closed contact 28 of said relay, over the line limb T ,'through the substation switchhook and transmitter, line limb T, over the tip side of the heavily marked circuit including strand L, and through the winding of supervisory relay 74 to ground. By the completion of this path in parallel to the winding of the cutolt relay, relay 7 1 is energized to'attract its contacts 7576. By thismovement of contact 76, a path for current is completed from the live pole of battery B through the right-hand winding of relay 73, contacts 77+? 8 of said relay, alternate contact 7 6, conductor 79, release magnet RM, closed contact 60, normal contact Get, wiper 19, contact 15 and normal contact 33 to ground. The resistances and other characteristics of relays 78 and RM are such that the former will be sufliciently energized to attract its contacts, while the 77-78 and 71'7 2, in turn followed by the closing of contacts 7182. The closing of contacts 80-72 completes apath-for current through the left-hand-winding of relay 73, contacts 80-72, the sleeve side of the heavily marked circuit, through the winding of cut-off relay 29 to ground, thereby maintain ing the relay 73 energized over a circuit independent of that through the calling station. As soon as relay 74 is energized, the movement of its contact 75 will complete a circuit for the calling lamp 83 extending from the live pole of the battery B through said call lamp, normal contact 84 of relay 70, and alternate contact 75 to ground,

thereby causing a display of the call lamp as an indication to the operator that connection is desired. As soon-as the operator observes the signal, she will depress her listening-key levers 85-86 to include her telephone set in circuit with the calling line. Any desired operators set may be employed. In the particular instance illustrated, a receiver 87, a windingof the induction coil 88,.

and a condenser 89 are adapted to be included 1n bridge of the link-circuit strands.

Another winding of the induct-ion coil.88 is included in .a local circuit with the battery 90 and the transmitter 91. The third Wind ing of the induction coil 88 is adapted to be included in a c1rcu1t between the live pole of the battery B and'groundupon the energiza-tion of test relay 92, which is normally connected to the tip side of the circuit. This ground connectlon is established to the contact 93 of said relay-92. Upon learning the wishes ofv the calling party, the operator contact of a jack 95 connected to said line.

Froman inspection of the diagram, it w ll be seen that the contacts of jacks 95 are connected to the opposite sides of the. line circuit' upon the selecting switch side of the cut-ofi' relay. Consequently, as soon as current. is supplied to the cut-otf relay, a potential above that of ground will exist ateach of the sleeve contacts of the line with which said relay is associated. Consequently, if the line tested be a busy line, the engagement of the tip of the plug 94; with the sleeve of the jack 95 will result in a flow of current over the tip side of the link-circuit, through normal contact 96 of super visory relay 70, and the winding of test relay 92 to ground; Relay-92 willthereby be energized momentarily to complete a mo-' mentary circuit through the tertiary .winding of the induction coil 88 and thereby cause the customary click in the operators receiver as an indication that the line Wanted is busy. In such event, the operatproil relay 29 of the called-for line, which may be assumed to be that indicated at the right in Fig. 1. The cut-oft relay will thereupon be energized with a consequent disconnec-- tion of the called-for line from the associ- IOU ated master-switch mechanism .and with the inserting the plug 94 into the jack 95 of the called-for line, the operator will depress her ringing-key levers 100101 and thereby include. the generator 102 and resistance 103 With thein bridge of the link-circuit.- parts so connected, a circuit for ringing current will extend from the grounded pole of the generator 102, through said generator, ringing-key lever 100, plug and jack tip contacts, alternate contact-30, line limb T, switclvhook 23, condenser 25,. call-bell 26, line limb T alternate contact 28, jack and plug sleeve contacts, ringing-key lever 101 and resistance 103 to ground. By rea-,

son of the character of current supplied by the generator 102, the call-bell 26 of the called-for line will be actuated as a signal to the called' for party, As soon as he responds by the removal of his receiver from its switch-hook, a pat'h for current, in parallel with that through the winding of cut olf relay 29 of the called-for line, will extend from closed contact. 28 of said relay, over line limb T through the transmitter and receiver at the substatiomline limb T, alternate-contact 30, jack and plug tip contacts,the

tipside of the. link-circuit, through the wind- .ingof tip supervisory relay 99-to ground. 1

Thiswill result in energizing said relay sufficiently to open its contact 98 and thereby extinguish supervisory lamp 97 \Vith the parts thus connected for conversation, transa mission current will be supplied from bat-' strands.

At the end of conversation, the restoration of the calling partys receiver will be instrumental in'interrupting the path for current through the. tip supervisory relay 74 and said relay. will be deenergized. Upon,

the retraction of its contact 75, a path for current will exist through supervisory lamp 106, closed contact 107 of relay 73 and normal contact 75 to ground,.'thereby lighting lamp 106. Likewise, upon the restoration of the called partys receiver to its-hook, the branch through the tip supervisory relay 99'will be interrupted and said relay will.

permit its contact 98 to again close and thereby cause the supervisory, lamp 97 to light -The lighting of both lamps 106 and i 97 constitutes a signal to theloperator to take down they connection.

The'supervisory relay and the cut-off relay 29 of the called line are thereupon deenergized. The deenergization of the latter results in establishing the normal line connections and placing: the line in condition for furtheruconnection as a calling or called line. The deenergization of the former interrupts the energizing -circuit of the supervisory lamp '9? and causes its "effac'ement. Since the connection is not taken down until. both supervisory lamps 106 and -9.7 are lighted, the deenergization of relay 70 will also complete a release circuit for tho associated selectmgswitch O. This circuit j parts are returned to normal.

complished by the mechanical relation of the parts .Which will hereinafter be more fully explained. During the release, wipers This she does by removing the plug94efrom the jack 95.

extends from the -live pole of the battery B through protective resistance 68, normal contact 69, contacts 71-82, normal contact 76, conductor 79, Winding of release magnet RM, closed contact 60, normal contact 64;, wiper l9,'contact 15, and normal contact 33 to ground. This causes the energization of release magnet RM; and by reason of the mechanical relation of the parts, this energization causes a movement of the spring contacts of the release switch RS to their normal positions, thereby interrupting the energizing. circuit of release magnet RM. --VVhen this occurs, the varlous switch TlllS 1s ac- 20, 21 are open circuit at contacts 65, 66, circuit for relay SR being closed through contact 59 (switch RS being shifted to normal on energization of magnet RM), alternate contact 58, relay SR to battery B. In this release operation, as soon as the sleeve side of the heavily marked circuit is interrupted at contact 66, the cut-off relay 29 of the calling line and the supervisory relay 73 of the associated link-circuit are denergized, the former to restore the line connections to normal, and the-latter to complete the restoration of the associated link-circuit apparatus to normal. Upon the complete secondary return movement of the wipers of the selecting switch C, the spring contacts of the secondary off-normal switch S0 are returned to normal; and upon the complete restoration of these Wi ers, the spring contacts of the primary 0 -normal switch P0 are returned to normal.

Obviously, in carrying out my invention according to the above description, any preferred construction 'of mechanical switch mechanisms may be employed for accomplishing the various functions therein in.-

dicated. However, for this purpose I preferably employ the switches illustrated in Figs. 2 to 8 inclusive.

Referring to Figs. 2, 3, 4, 7 and 8, which illustrate a preferred construction of a line" selecting switch C, 108 designates a suitable supporting frame for the switch structure. This structure includes, as previously indicated, thefprimary magnet PM, secondary magnet SM and release magnet RM, all suitably carried upon the frame 108. This frame also carries the fixed contacts 15, 16 and 17, Whiclrare arranged in a bank 109 with their free ends adapted for the attachment of suitable conductors and witlrtheir inner contacting ends terminating in a spherical surface. These contacts are suitably insulated from-each other and c0- opcrate with the wipers '19, 20 and 21, which are pivoted at the center of rotation of the spherical surface to the lower end of a rotary shaft 110, suitably journaled in the| frame 10.8. The wipers are rotatable with the shaft in a primary (horizontal) direction and about the pivot 111'at the lower end of the shaft'in a secondary (vertical) direction. The secondary movement accomplished through the agency of a longitudinally movable shaft 112 having a broad foot 113, -which engages ah anti-friction the roller 114, no matter what the positioir of the wipersmay be. In addition to the wipers and bank contact-s thus provided, the

frame 108 also carries a horizontal row of wiper 18. is capable of a horizontal, or pri-' mar), movement only and does not partake of the secondary movement of the wipers 19, 20 and 21. The mechanism associated with the primary 'magnet PM; by which the shaft 110 is given its primary step-bystep movement, as clearly illustrated in Figs. 3 and 7, comprises an actuating pawl 116. carried by the armature 117 of the magnet PM, and adapted to engage the teeth o-fthe ratchet wheel 118 to step the shaft 110 around. pressed, cooperates with the beveled stop 119 to give the ratchet wheel 118 a single step upon each energization of thepriinary .magnet. The shaft 110 is retainedin its various positions by the retaining pawl 120 which is normally spring-pressed into engagement with the teeth of the ratchet wheel. The upper end of the shaft. 110

carries a member 121 having a projection 122 which normally maintains the spring contacts 50 and 51 of the primary off-now mal switch P0 in their normal posi tions, but which. upon the first movement of the shaft, allows them to move under their inherent tension to their alternate positions. The secondary magnet SM, through the agency of its armature 123, ac tiiating pawl 12t and the ratchet teeth 125 on the shaft 112, steps the latter downward to carry the contacting ends of the wipers 19. 20 and 21 in a secondary direction to the desired position. A suitable retaining pawl 126, pivotally mounted between the.

frame 108 and abracket 127 carried thereby, engages the teeth I28 on the shaft 112 to hold it in its different positions. The shaft 112 is also provided with a suitable spline The pawl 116, which is spring.

129, which, after the first movement of the shaft, engages the teeth of the ratchet-wheel 118 to lock the shaft against rotation. By this means further movement of the wipers in a primary direction is prevented as soon as they have begun their movement in a secondary. direction. The frame 108 also carries the contacts of the secondary ottnormal switch S0. The contacts 58-431 of'this switch are held against their spring tension in their normal positions through the agency of a projection 130 carried by the upper end of the shaft 112. The outer end 131, which in turn presses the contact springs 58-61 into their normal pos'ltlons. The vibratory circuit of the primary magsprings 57 which are actuated by the projecting end of the armature- 117. The vi bratory circuit of the secondary magnet SM, is completed through the contact springs 67 carried bythe magnet frame and cooperating with the armature 123. This 108 also carries the contact springs of'the release switch RS. As previously indicated, the contacts 5960 of this switch have a spring tension tending to hold them in their alternate. positions, but are normally held out of such position through the agency of a catch lever 133. Upon the energization of the primary magnet PM, this catch is disengaged and the springs are allowed to move to their alternate positions. This is brought about through the agency. of the armature 117 of the primary magnet and the associated member 137. The member 135 is pivoted at an intermediate point. to the lower end of the armature 134: and extends beyond the contact spring 59, and into a position to draw it to its normal poi sition upon the attraction of the armature 134. This armature is retracted by a suit able leaf spring 135. The catch lever 133,

the post 136 carried by the frame 108'," is moved from its retaining position so as to allow the springs 5960 of the release switch RS to move to their alternate positions upon the first energization of the primary magnet PM. This is brought near its center upon the frame 108, and having one end lying in the path of movementof the armature 117 of the primary inag net.- Its opposite end is provided with an upturned projection 138 which bears against the under side of the catch lever 133. Upon lever 137 is rocked about its pivot and its upturned end 138 rides over the inclined surface 139 on the under side ofthe catch lever 133; so'as to rock thelattenabout its pivot and thereby release the springs 59-430 of this projection normally engages a pin armature asclearly illustrated, is retracted by a suitable leaf spring 132. The framenet PM is completedthrough the contactwhich is pivoted at an intermediate point to about by the lever 137 pivotally supported '12 "the first movement of the armature 117,

and .allow them to move to their alternate positions. As previously indicated, after the wipers have been giventheir primary and'secondary movements, they are retained in position by means of the primary retainingjpawl120 and the secondaryretaining.

, pawl 126.. In giving the'wi mary movement, the shaft 112 is rotated against the tension of a spiral spring 140 contained in a suitable case 141 carried by the frame 108. Similarly, in giving the wiperstheir secondary movement they 'ar'e rotated against the tension of a spiral spring 142 located about the pivot 111. and co operating between the lower end of-the shaft and said wipers. In View of this, it is therefore only necessary,'in order to return the wipers and other switch parts to theirnorma positions, to disengage the retaining pawls 120126. As prevlously indicated,-

this is brought about upo'n'the deenergization of the release magnet RM. Upon such release, the retraction of the armature 134 member is arranged to engage the retaining draws the member 135 with it and this pawls at this time, and to move them out of their engaging positions. To this .end,

' the primary retaining pawl 120 is provided with a tail having an upturned .,end 143 which is adapted to pass through a cooperating opening 144 in the member 135. Similarly, the secondary retaining pawl126 is provided with a tail having a-similar upturned end 145, similarly'adapted to pass, into an opening 146 in the member 135. Upon the attraction of the release magnet armature 134, the' member 135 passes over the upturned ends 143,145 until the openings 1444 146 come into registration therewith. .The member 135 by, the action of its spring 147, moves downward far enough to-engage the projecting ends of the pawls.

.Then upon the retraction of the armature 134, these pawls are movedout ofsengaging position and through the agency of the springs 140,-142 the wipers are returned to their normal'positions. As soon as the wipers reach the end of their secondary return movement, the contacts of the secondary off-normalswitch S0 return to normal,

and, as soon as the wipers reach the end of their primary return movement, the con: tacts of the primary off-normal switch PO 7 are returnedto'normal. For convenience in establishing electrical connection with the various parts of the switch, terminal con necting strips '148149 are carried by, and.

suitably insulated from ,the frame 108.

To provide against the' possibility of improper operation ofthe selecting switcheswhere, as the result of two calls being 'ini tiated at practically the same time, the wipers of twoswitches stop at the same group of bank contacts and begin their sec rs their pri- 1 ondary movement, (instead-of the wipers of one of the switches continuing their primary movement to another group) thereby caus:

ing the wipersof two switches to attempt.

selection of the same calling line, I may employ any desired means, such as having the ('l:6., not connected to any line) whereof 15 and 17 In such case wipers 19, 20 and 21, would connect with these contacts on a tenth secondary step and the switch be automatically released as will befevident from the release operations already described.

Referring to Figs. 5 and 6 which illustrate the master-switch mechanism B, it will be observed that the contacts 12- upon the base 151 and arranged-so as to present their contacting ends for engagement with the cooperating wipers 10.1l. These contacts are suitably insulated from each other and have their outer ends arranged for the attachment of suitable conductors. The wipers'10-11 are suitably mounted upon,

and insulated from the shaft 152 journaled at its opposite ends in the base 151 and in the bracket 153 carried by said base. The wipers are adapted to be moved from their normal non engaging positions to their variwould be permanently grounded, while 16would-be on open circuit.

, 13- are mounted in an arcuate frame 150, suitably carried last'contact set 15', 16', 17- a dummy set ous connecting positions by the mechanism but when in its retracted position, is with-' drawn from engagement by the stop 159 r1ding upon the adjacent beveled surface of the pawl. This forward. stroke is limited by any suitable means as, for instance, by the pawl engaging-a portion of the bracket 153. The vibratory circuit of the motor magnet M is completed through the spring contacts 45' carried by the magnet frame and actuated by the projecting end 160 of the armature 156. The base 151 also carries the release magnet RMwhich has a spring retracted armature 161 provided with a spring extension 162 whichcotiperates with the retaining pawl 163 and thespring contacts 46-4 which are also suitably-mounted upon the base 151.- The yielding member 162 is r0- vided with an angular projection 164 w ich cooperates with a lateral projection'l65. carried by the tail of the retainingpawl 163.

'An extension 166 of the driving pawl 157 is also provided with a lateral pro ection 167 which engages the right-hand face of the yielding member 162. The arrangement of these parts is such that upon the first attraction of the armature 156, the member 162 is carried toward the left far enough to allow the lateral projection 165 on the pawl 163 to disengage with the shoulder formed 1 by the lower face of the angular projection 164. This results in freeing the pawl 163 and thereby allowing it to move under the force of its spring 168 into position to en; gage the teeth of the ratchet wheel 158. This movement of the yielding member 162 allows the contact springs 46- 17 to close with their'cooperating springs. As soon as the retaining pawl 163 is free, its lateral projection 165 engages the outer or righthand face of projection 164 and thereby holds the member 162 far enough to the left to allow the contact springs 4647 toremain in their contacting position. Thus it will be seen that as soon as the driving pawl 157 has made one stroke, the retaining pawl 163 is free to act and the springs 4647 are moved to their closed positions. Withthe parts in this condition, the subsequent attraction of the armature 161 ofthe release magnet carries the projection 164:.far enough to cause its lower face to engage the upper face of the lateral projection 165 on the retaining pawl 163, so that upon the retraction of said armature, the retaining pawl is moved from its engaging position. As soonas the projection 16 1 passes beyond projecti'on 165 and thereby allows the yielding member 162 to move slightly toward the right, it will be apparent that contact springs 4647 will be opened. Thus upon the energization of the release magnet RM, contacts 46-47 are opened, and upon the deenerglzation of said magnet-,.the retaining pawl-163 disengages the ratchet wheel 158 and allows thewipers 11 to return to normal under the retracting action of the spring 1. It

should also be noted that as soon as ratchet wheel 158' and shaft 152 begin to rotate, contact 4:2 is allowed to open since at this time the stop 169 is moved out of engagement with contact spring 42.

Obviously in the'practice of my invention many alterations and modifications may be made both in the circuit arrangement and the mechanical structure ofBthe device without departing from the spirit and scope of the invention, thus, for example, the several batteries shown herein as separate and distinct may be one and the same. Other like -modifications may be made. I therefore, do

not wish to be limited to the specific matter disclosed, but aim to cover bythe terms of the'appended claims all such alterations and modifications.

What I claim as new and desire to secure by Letters Patent of the United. States, is:

1. A telephone exchange "system comprising a plurality of telephone lines, a plu ralityof selecting switches, each-having as position after each selecting operation, means actuated duringthe-operation of an actu-. ated selecting switch to 'free said masterswitch for further use, and means for permitting the further operation of said -mas-' 'ter-switch during the use of said actuated selecting switch onlyin response to an additional call. I 2. A telephone exchange system comprise ing a plurality of telephone lines, a plurality of selecting switches each having ac: cess to said lines, a master-switch for selecting and starting idle selecting switches to establish connections with" calling lines, means for restoring said master-switch to a definite position after each selecting oper-. ation, a control switch associated with each of said lines for causing the operation of said master-switch, means actuated during the operation of any one selecting switch to free said master-switch for further use in selecting and starting a second selecting switch, and means forpe'rmitting such fur: ther operation of said master-switch during the use of said actuated selecting switch only in response to the manipulation of asecond control. switch.

3. A telephone exchangesystem comprising a plurality of telephone lines, a plurality of selecting-switches, each having ac- 'cess to said lines, a master-switch for select- 1 4. A telephone'exchange system comprising a plurality of telephone lines, a plu rality of associated interconnecting switches, a master-switch for selecting and starting idle ones of said switches, means for restoring said master-switch to adefi'nite position after each selecting operation, a plurality ("if control devices for individually causing the operation of said master switch, means actuated during the operation of an actuated switch to free said master-switch for further operation in selectingand starting another idle nterconnecting switch, and

means for permitting such further operation during the use of saidactuated selectingswitch. only in response to the inanipulation of a second control device.

5. A telephone exchange system comprising a plurality of electrically controlled operating devices, a master-switch for selecting and-starting idle ones of said devices.

means for restorin said master-switch to a definite position after each selecting opera- .tion,,a plurality of-control devices for 1ndividually causing the operation of said master-switch, means actuated during the operationof an actuated operating device to free said master-switch for further operation in selecting and starting another idle operating device, and means for permitting such further operation during the use of said actuated operating device only in response to the manipulation of a second control device.

6. A telephone exchange system comprising a plurality of electrically controlled operating devices, a plurality of master switch passive contacts severally assigned to said operating devices, a cooperating movable cont'act-iwrmallyoccupying a definite position, means for moving said movable contact over said passive contacts and stopping it in engagement with the passive contact corresponding to an idle one of said operating devices, a plurality of control devices for individually causing the operation of said master-switch, means operated during t e operation of any one of said operating devices to return. said movable contact to its normal position, and means for preventing another advance of said movable contact during the use of a previously actuated operating device except in response tothe actuation of a second control device.

7. A telephone exchange system comprising a plurality of electrically controlled oprating devices, a plurality of master-switch passive contacts severally assigned to said operating devices, a cooperating movable contact normally occupying a definite posi tion, means for moving said movable contact over said passive contacts and stoppingzit in engagement with the passive contact corresponding to the first idle one of said operating devices, a plurality of control devices for individually causing the operation 'of said master-switch, means operated during the operation of any one of said operatingdevices to return said movable contact to its normal position, and means for preventing another advance of -sa1d movable contact.

during the use of a previously actuated operating device except in response to the actuation of a second control device.

8. Av telephone exchange system comprising a plurality-of telephone lines, a plurality of associated interconnecting switches,

assive conswitches, a

a plurality of master-switch tacts severally assigned to sai cooperating movable contact normally occupying av definite position, means for moving said movable contact over said passive contacts and stopping it in. engagement with the passive contact corresponding to an idle one of said interconnecting switches, a plu rality of control devices for individually causing the operation of said master-switch, means operated during the operation of any one of said interconnecting switches to re turn said movable contact to its .normal 0- sition, and means for preventin anot ier advance of said movable cont'act (lining the use of a previously actuated interconnecting switch except in response to the actuation of a second control device.

9. A telephone exchange system comprising a plurality of telephone lines, a plurality of associated interconnecting switches, a plurality of master-switch passive contacts severally assigned to said switches, a cooperating movable contact normally occupying a definite position, means for moving said movable contact over said passive contacts and stopping it in engagement withthe. passive contact corresponding to the first idle one'of said interconnecting switches, a-

p'lurality of control devices for individually causing the operation of said master-switch, means operated during the operation of any one of said interconnecting switches to return said movable contact to its normal position, and means for preventing another advance of said movable contact during the the passive contact corresponding to an idle one of said selecting switches, a plurality of control devices for individually causing the operation of said master-switch, means operated during the operation of any one of said selecting switches to return said movable contact to its normal position, and means for preventing another advance of said movable contact during .,the use of a previously actuated interconnecting switch except in response to the actuation of a second control device.

11. A telephone exchange system comprising a plurality of electrically controlled devices, a master-switch for controlling said devices having a normal position and positions corresponding to said devices, control -devices for said master-switch, means responsive to the operation of a control device to cause a movementof said master-switch for controlling said switches having a nor mal position and positions corresponding to said switches, control devices for individually operating said master-switch, means responsive to the operation of a control de vice to cause a movement .of the masterswitch from its normal position to a pos1- tion corresponding to an idle.interconnecting switch, means actuated thereby to start.

the operation of said idle interconnecting switch, means actuated by the startlng of said interconnecting switch to restore said" master-switch to its normal position, a relay for said master-switch, and means for deenergizing said relay by said start ng to operatively dissociate sald master switch and said control device.

13. A telephone exchange system comprisinga plurality of telephon lines, a pinrality of selecting swltches each having access'to said lines, a master-switch for con trolling said switches having a normal.p o sition and positions corresponding to said switches, control devices for individually .operating said master-switch, means responsue to the operation of, a control device to cause a movement of the master switch from its normal position to a position correspond:

ing toan idle selecting switch, means act-uated thereby to start the operation ofsaid .idle selecting switch, means actuated, by the starting of said selecting switch to restore saik'Lmaster-switch to its normal position, a" .relay initially energized responsive to"sa d control device to start said'movementof said master-switch, a neutralizing winding therefor, andmeaiis conteolled by the starting of the idle selecting switch to cause a flow of current through said winding'whereby said relay is deenergized.

14:. A telephone exchange system comprising telephonelines, a plurality of selecting switches each having access to said lines, a master-switch for start-ing said switches having a normal position and positions corresponding to each of said switches,

n eans responsive to the initiation of a. call to initiate travel of said mastenswitch to se- 6 lect and start an idle selective switch, a relay of said master-switch controlling said travel, a release magnet for restoring said master-switch, a circuit for said magnet, and a switch contact of said circuit maintained open by said relay during the travel of said switch.

15. A telephone exchange system comprising telephone lines, a plurality of selecting switches each having access to said lines, a master-switch for starting said switches having a normal 'position and positions corresponding to each of said switches,

means responsive to the initiation of a call to initiate travel of said mastersw'it-ch to select and startan idle selective switch, a relay of said master switch controlling said travel, a circuit forenergizin said relay, a locking switch contact of sai .relay. for holding it energized until said master-switch selects an idle selecting switch,

and an ofi'-normal contact of said master switch actuated on the first'step thereof to open the initial energizing circuit of said relay.

16. A telephoneexchange system comprising telephone lines, a plurality of selecting. switches each having access to said lines, a

master-switch for starting said switches havmg a normal position and positions corresponding to each of said switches, means responsive to the initiation of a call to initiate" travel of said master-switch to select and start an idle selective switch, a relay of said master-switch controlling said travel, a circuit for energizing said relay, a lockingswitch contact of said relay for holding it energized until said master-switch selects an ldle selecting. switch, an off-normal contact of said. master-switch actuated on the first a. step thereof toeopen the initial energizing,

circuit of said relay, a release magnet for restoring said master-switch, a circuit for said magnet, and a switch contact of said circuit maintained open by said relay during the travel of said switch' 17. A telephone exchange system comprising telephone lines, a plurality of selecting switches each having access to said lines, a

master-switch for starting said switches having a normal position and positions corresponding to each of said switches, means re.- sponsive to the initiation of a call to initiate travel of said master-switch to select and startan idle selective switch, arrelay of said mastenswitch controlling said travel, a circuit for energizing said relay, an cit-normal contact of said masterrswitch actuated on the firststep thereof to open the initial en.- ergizing circuit of said relay, and a release magnet for restoring said masterswitch, a

circuit for said magnet, and a switch contact of said circuit maintained openhy said relay during the travel of said switch.

18. The. combination. in a selective switch with an operating relay R, for determining the travel of said switch, of a release mag- In witness whereof, I hereunto subscribe net RM for returning said SWltCIlII to nornifal, my name this 1st day of December 1906'. contacts selectable by said switc means or denergizing said relay 0n selerition .of an ALFRED DYSON idle contact, and an armature switch con- Witnesses.

- tact closed on deenergization thereof to en- L. D. KELLQGG,

ergize said release magnet. CAROLYN WEBER. 

